Hong Kong’s weather forecaster may issue the No 3 typhoon warning signal on Monday as Tropical Storm Fengshen moves closer to the coast of Guangdong, with temperatures set to fall to about 20 degrees Celsius (68 Fahrenheit).

The Hong Kong Observatory said on Saturday that Fengshen, which means “the god of wind” in Chinese, would come within 800km (497 miles) of Hong Kong the following day and would be closest to the city on Tuesday.

“With Fengshen edging closer to the coast of Guangdong later on Monday, the Observatory will consider issuing the No 3 warning signal directly to replace a strong monsoon signal by then, without issuing the No 1 warning signal,” the forecaster said.

Tse Kwan-shu, a scientific officer from the Observatory, said Hong Kong would affected by two weather systems in succession: a monsoon, which will dominate the coast of Southern China on Sunday, and the tropical storm.

“The wind intensity of the strong monsoon signal is higher than that of T1. Since there is no sign of weakening, the No 3 signal will be issued directly,” he said.

Hong Kong is expected to be persistently windy and experience cloudy weather with rain early to mid-next week under the combined effects of Fengshen and the monsoon.

Temperatures will drop appreciably to around 20 degrees Celsius in the urban areas mid-next week and a couple of degrees lower in the New Territories.